Raphael Gobat et al 2021 ApJ 921 157
The possibility of life being seeded by impacts from another star system varies wildly depending on where you are in the galaxy, but the probability of life arising via panspermia rather than prebiotic evolution tends to be low overall.
Manasvi Lingam et al 2021 ApJL 921 L41
The number of electrons available to respond to excitation by stellar photons in molecules that participate in photosynthesis is different on planets orbiting other stars, with M-dwarf planets requiring twice as many delocalized electrons.
Sean Jordan et al 2021 ApJ 922 44
The best way to distinguish between an exo-Venus and an exo-Earth may be to search for sulfur compounds like SO2 and H2S — these compounds are destroyed by the radiation from Sun-like stars but could persist around cooler stars.
Melinda Soares-Furtado et al 2021 AJ 162 273
Enhanced lithium abundances in evolved stars are unlikely to be due to the engulfment of metal-rich Jupiter-mass planets, but this phenomenon could boost lithium abundances in solar-mass stars just about to leave the main sequence.
Brian C. Lacki et al 2021 ApJS 257 42
The 816 targets in the catalog comprise archetypical, superlative, enigmatic, and everyday examples of a wide variety of astrophysical sources, which can be used to guide searches for extraterrestrial intelligence.
Navdeep K. Panesar et al 2021 ApJL 921 L20
Small-scale solar heating events dubbed “campfires” may encompass a variety of dynamic features that contain enough energy to heat a localized region of the solar atmosphere to 500,000–2,500,000K for roughly 10 minutes.